Combined effect of undersized surgical technique and axial compression on the primary implant stability and host bone architecture

Aim: The aim of this study was to investigate the combined effect of the lateral-compression of host-bone (undersized-osteotomy-preparation) and axial-compression of host-bone (not drilling the full length of the implant) on the primary-implant-stability and the host-bone-architecture. Materials and Methods: In this experimental-study, 44 dental implants (diameter-4.2 mm; length-10 mm; Dyna®) were installed in the femoral-condyles of four cadaver-goats using four different surgical approaches (11 implant/surgical approach; n = 11). Approach-1: Standard preparation according to the manufacturer's guidelines. The bone-cavity was prepared up to 10 mm in depth and 4 mm in diameter. Approach-2: Preparation up to 8 mm in depth and 4 mm in diameter. Approach-3: Preparation up to 10 mm in depth. Approach-4: The bone-cavity was prepared up to 8 mm in depth and 3.6 mm in diameter. Insertion torque (n = 11), removal torque (n = 7) and % bone-implant contact (n = 4) measurements were recorded. Bone architecture was assessed by micro-computer tomography and histological analysis (n = 4). Results: For approaches 2, 3, and 4 (P < .05), insertion-torque values were significantly higher as compared to approach 1. Regarding the bone-implant-contact percentage (%BIC), approach 3 and 4 were significantly higher compared to approach 1 and 2 (P<.05). For approach 2, the %bone volume (%BV) was significantly higher as compared to approach 1 (P<.05) for the most the inner zone of host bone in proximity of the implant. Conclusion: Lateral and axial compression improved the primary-implant-stability and therefore this new surgical-technique should be considered as an alternative approach especially for placing implants in low-density bone. Nevertheless, additional in vivo studies should be performed

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

Background Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. Methods We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). Findings In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]). Interpretation In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. Funding British Journal of Surgery Society